What do homologous chromosomes have in common?

Homologous chromosomes are pairs of chromosomes, one inherited from each parent, that contain the same sequence of genes. Each chromosome in the pair carries the genes for the same traits, which allows them to align during meiosis, facilitating genetic diversity through recombination. However, the alleles—the different versions of a gene—located at corresponding positions on homologous chromosomes can vary. This means that while the genes (and their locations) are the same, the specific versions of those genes (the alleles) may differ between the two chromosomes.

This distinction is crucial because it allows for genetic variation within a species. For instance, one chromosome may carry an allele for blue eyes while the homologous chromosome may carry an allele for brown eyes. The combination of alleles inherited from both parents contributes to the genetic makeup of the offspring, which is a fundamental aspect of inheritance.

The other options do not accurately describe homologous chromosomes: they do not consist of different alleles for all genes, they are not identical in DNA sequences (as they can have variations), and both chromosomes from the pair are present rather than just one.